In history and in many black American families, there's talk of black people passing for white, especially during the days of Jim Crow laws or slavery when it benefited them or even saved their lives.

But not as much has been written about the white people who pass for black or adopt black culture — from celebrities who adopt traditionally black hairstyles and vernacular, or, as social media has been abuzz with since Thursday, Rachel Dolezal, the NAACP Spokane, Wash., branch president whose parents say she is white.

English professor Alisha Gaines, who is publishing a book about white people who pass for black, says the phenomenon is rooted in a need to identify and empathize with black culture. Some people throughouthistory have passed for black as a way to immerse themselves in the experience, says Gaines, who teaches at Florida State University in Tallahassee.

One of the people referenced in her book, Black for a Day: Fantasies of Race and Empathy, is Grace Halsell, a late journalist who posed as a black woman for a few weeks in the deep South and wrote about her experiences in a book titled Soul Sister.

Some hailed Halsell as courageous. Others scoffed, saying one could not appreciate the full black experience in such a short time and in such a simplistic manner.

There have been others through history, too, such as late journalist John Howard Griffin, who darkened his skin and traveled through the segregated South, as chronicled in his 1961 book, Black Like Me, or late R&B musician Johnny Otis, who presented himself as black, says Gaines.

"The people that I'm studying are coming from a perverted place of empathy," Gaines says. "The problem is even though they darken their skin — Grace Halsell, she still has the privilege of taking it off, and therein lies the problem," Gaines says. "Rachel is considered an activist. At the same time, she can take that curly wig off, which is kind of the issue I see here."

The main reason people choose to pass for black is they have a need or desire to promote civil rights and racial justice, says Marcia Dawkins, author of Clearly Invisible: Racial Passing and the Color of Cultural Identity.

"We have a lot of stories during segregation of people choosing to pass or identify as black in order to promote civil rights and just to help bring attention and awareness in numbers," says Dawkins, clinical assistant professor at the Annenberg School for Communication at the University of Southern California.

Dawkins speculates that Dolezal wanted to fight for racial justice and may have felt that altering her identity was the best way to be taken seriously in this.

"I think in 21st century America where the demographics are changing, particularly in some parts of the country that are resistant, like a New York or a Los Angeles, it can be hard to be an ally," Dawkins says. "There might not be an easy way to do that and be taken seriously."

Author and educator Nikki Khanna believes it also can be about being accepted.

"Maybe for this particular woman — it seems as if she cares about African-American issues, she heads the chapter of the NAACP in Spokane, I don't know if she felt that was her way of fitting in," says Khanna, who has studied how biracial Americans identify in terms of race.

"You don't have to be black to lead a chapter of the NAACP and you don't have to be black to fight for those issues," adds Khanna, an associate professor of sociology at the University of Vermont. "She could have just been herself."

Added to the pot is debate that has come from what some call appropriation of black culture, such as when a blog recently credited designer Marc Jacobs with inventing the Bantu knot, a style that originated in Africa more than 1,000 years ago, or Australian rapper Iggy Azalea, who critics say has heavily borrowed from the style and dress of black rappers.

These instances are examples of white people adopting black culture because of its "cool factor," Gaines says.

It can be a money maker, too, especially when it comes to adopting hair and clothing styles and music, Dawkins says.

"Blackness seems to pay — except if you're black," Dawkins says. "It's a lucrative identity to be part of unless it's issues of police brutality."

The academics speculate that Dolezal's actions, if accurately portrayed by her parents, may have something to do with tensions with relatives.